Duluth, MN (NNCNOW.com) --- Enbridge hopes it's proposed sandpiper oil pipeline, planned to bring North Dakota Crude to Superior, can have oil flowing by early 2016.But much has to be done before that can happen... including a full environmental survey of the route.

Crews have been walking the route of the proposed 616-mile pipeline since the spring of 2013.

"It's real important that we know where wetlands are located, that we know the protected species, endangered species and critical habitats so we know where those are and we can plan to either work around them or minimize the impacts" said Community Relations Consultant for Enbridge, Christine Davis.

The crews are made up of biologists and archaeologists looking for anything significant that could disrupt the pipeline's construction.

So far Enbridge representatives say small artifacts from Native American settlements along with some small biologically sensitive wetlands have been found, but nothing of serious significance to the line's construction.

"Usually sites are relatively small. If you can imagine an old tee-pee ring or a campsite, so generally we're talking shifts of only 50 to 100 feet at most" said Senior Manager, Environment, Paul Meneghini.

Project managers say they also have ways to avoid biologically sensitive areas.

"Maybe we can alter our construction technique, maybe we drill beneath them a lot deeper so we're not altering the soil or again, minor reroutes, very small changes, 50 feet here or there to the pipeline corridor itself" said Meneghini.

Up to 100 people covering a swath of about 250 feet are walking the proposed route each day.The surveying has to be coordinated with landowners and Enbridge says 96 percent of landowners have allowed surveyors on their property. Surveying will end by the end of the year.

"We'll have basically 95 to 98 percent of the properties will have been surveyed and will obtain the necessary data to build our applications for all the various permits that we'd need" said Meneghini.

Until then, surveyors will keep scouring the route.

The sandpiper line is estimated to cost two-point-six billion dollars and will move nearly 16 million gallons of oil each day.